How to move baked curves in graph editior?
I do a lot of sound baking, and always bake at frame 1 then use the NLA editor to change start frame, simply and quickly.  You don't want to be baking large sound files again to move a frame to the left 8^).

If you are going to use the NLA, it  also pays to create an empty action (how you want it to be with silence) and add that to the stack.